Field of the Invention
The present invention relates to a control of a hybrid vehicle having a first rotational shaft connected at its one end to an output shaft of an engine via a first clutch and a second rotational shaft connecting the other end of the first rotational shaft to a transmission, wherein a driving electric motor is connected to the second rotational shaft via a second clutch.
Description of the Background Art
There has been a generally known hybrid vehicle having an engine and a driving electric motor as driving sources and traveling with a driving force transmitted to driving wheels through a power transmission passage via a transmission. For example, when such a hybrid vehicle travels on a road surface including irregularities such as a wave road, there is a case where repeated slipping and gripping of driving wheels cause cyclical torque fluctuations to be transmitted back from the driving wheels to the driving sources.
Particularly, in a case where a clutch having therein a torque limiter damper is provided a transmission and a driving source, receiving torque fluctuations exceeding torque which is allowable in the torque limiter damper may cause a contact between a member, which is movable in a twist direction of the torque limiter damper, and its stopper, thereby resonance occurs in the rotational shaft between the transmission and the driving source. Accordingly, great torque may be given by the rotational shaft.
With regard to such a problem, for example, Japanese Patent Laying-Open No. 2009-040174 discloses technique of lowering an output of an engine when a detection result by a detection device for detecting irregularities on a road surface causes cyclical torque fluctuations in an output shaft.